Processed fiber product, and method for production thereof

ABSTRACT

A processed fiber product having excellent strength, water-absorbability and washing durability can be produced by attaching a partially hydrolyzed product of a wheat protein to a fiber and then allowing a transglutaminase to act on the fiber.

CROSS REFERENCES TO RELATED APPLICATIONS

This application is a continuation of International Patent ApplicationNo. PCT/JP2008/071282, filed on Nov. 18, 2008, and claims priority toJapanese Patent Application No. 299808/2007, filed on Nov. 19, 2007,both of which are incorporated herein by reference in their entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to processed fiber products and a methodfor producing the same using a transglutaminase and a protein orpeptide.

2. Discussion of the Background

Polyester appeared as the last clothing fiber substrate in the 1950s,and since then no novel significant fiber substrate has been developed.Since the 1950s, insufficient properties of fiber substrates per se havebeen improved, for example, by modifying a fiber formation proceduresuch as a spinning procedure or by performing a so-called fiberprocessing for chemical functionalization. Methods for improving thewrinkle resistance of cotton, methods for preventing shrinkage of sheepwool, processes for chemically improving luster or slimy feel of asurface of nylon or polyester, etc. have been widely used.

So-called enzymatic processes, which use an enzyme for reducing a defectof a clothing material of a natural fiber target, were developed in the1990s. Processes using a cellulose-hydrolyzing enzyme for partiallyhydrolyzing a surface of a cellulose fiber target such as cotton toobtain a good softer texture, and processes using a protein-hydrolyzingenzyme for partially modifying a cuticle surface of a sheep wool targetto improve the washing shrinkage of sheep wool, etc. have been studiedand partly put into practical use. Also uses of synthetic fiber targetshave been spreading in such processes. Though synthetic polymers havebeen considered to be not useful as the substrate, some polymers havebeen found to be capable of interacting with an enzyme. Thus, attemptsto enzymatically modify a surface of a target of nylon, acrylic,polyester, etc. have been performed.

The use of the enzymes has been spreading in the fiber processes.However, most of the enzymes for the above processes are hydrolysisenzymes that act only to cut the fiber substrate surface moderately, andthus the application and function thereof are severely limited.Therefore, an enzyme for catalyzing a chemical binding reaction,different from the hydrolysis enzymes, is needed to add a non-intrinsicfunction to the fiber substrate.

Transglutaminase is one of some attractive enzymes capable of satisfyingthe above demand. Transglutaminase acts to bond a glutamine residue anda lysine residue in a protein or to catalyze introduction of a primaryamine to a glutamine residue. Thus, transglutaminase has a highpotential to act upon a polyamide-based fiber substrate, therebyactively adding a new function in the fiber processing. In fact, severalnovel processes using transglutaminase for a fiber substrate such assheep wool have already been proposed in the fiber field.

Transglutaminase catalyzes the binding reaction between the glutamineand lysine residues, and thus may act upon a fiber substrate having theglutamine and lysine residues or the like. An advantageous effect oftransglutaminase has already been found. For example, when a sheep wooltarget is practically treated with transglutaminase, the glutamine andlysine residues in the sheep wool substrate are crosslinked by theenzyme-catalyzed reaction to increase the strength of the sheep wool(see, Enzyme and Microbial Technology, 34 (2004) pp. 64-72).

The novel function-added processing utilizing the above advantageouseffect cannot be achieved by using the cellulose- or protein-hydrolyzingenzymes, which have been studied for practical use. This processing canbe expected to further progress. However, the fiber substrate used inthe processing must have both the glutamine and lysine residues, andthereby is limited to some natural fibers such as sheep wool.

Polyamide fibers such as silk and nylon other than sheep wool do nothave a sufficient amount of the glutamine and lysine residues or thelike interacting with a transglutaminase. Thus, when such a polyamidefiber substrate is directly treated with a transglutaminase, thecrosslinking reaction cannot proceed. To accelerate the binding orcrosslinking reaction of such a substrate using a transglutaminase, athird component having a large amount of the lacked reactive residue hasto be added thereto. For example, a silk fiber substrate contains lysineand glutamine residues only in small amounts, whereby the residues arenot likely to react in a transglutaminase treatment. When the silk istreated with a peptide containing a glutamine and lysine in largeamounts beforehand and then subjected to a transglutaminase treatment,the densities of the reactive residues are increased, and the fibersubstrate and the third component undergo the binding reaction together,to cause the crosslinking effectively. Furthermore, when variousfunctional substances are added to the additional third componentbeforehand, the functional substances may be effectively introduced tothe fiber substrate in the enzyme-catalyzed reaction.

Even with a synthetic fiber substrate such as nylon it is expected thatthe residue of the synthetic fiber substrate is reacted with a thirdcomponent by the addition of the third component if the synthetic fibersubstrate has a reactive residue serving as a substrate of thetransglutaminase, and it may become possible to effect synthetic fibersubstrate crosslinking via the third component or effective introductionof the functional substance as in the case of the silk.

Based on this standpoint, JP-A-9-3772 proposes a method involvingcoating a polyester surface with a gelatin, and discloses that a fiberwith high moisture permeability and absorptivity can be obtained by thecoating. In this method, the polyester surface is coated with ahigh-concentration (30-wt %) aqueous gelatin solution containing atransglutaminase in view of improving the film formability. However, thecoating with the high-concentration aqueous gelatin solution is not apractical method because the solution is often converted to the gelstate or solidified on a knife coater in the coating process. Inaddition, in this document, the durability of the resultant coating isevaluated only with respect to dissolution in 90° C. hot water, andwhether the effect of the coating is maintained in a practical treatmentsuch as washing is not disclosed.

In view of avoiding the disadvantage of the high-concentration aqueousgelatin solution, JP-A-9-3773 proposes a method in which a polyester isimmersed in a 3-wt % aqueous gelatin solution containing atransglutaminase. However, in this document, the durability of theresultant film is evaluated only with respect to dissolution in 90° C.hot water, and whether the effect is maintained in a practical treatmentsuch as washing is not disclosed.

Thus, as is clear from the above methods, the moisture permeability andabsorptivity of a fiber can be increased by coating the fiber with ahigh-concentration gelatin solution. However, it is true that theresultant fiber is poor in wash durability and cannot maintain the wateror moisture absorptivity.

SUMMARY OF THE INVENTION

Accordingly, it is one object of the present invention to provide novelmethod for easily producing a fiber excellent in strength, waterabsorptivity, and wash durability with low cost.

It is another object of the present invention to provide novel fiberswhich are excellent in strength, water absorptivity, and wash durabilityat low cost.

These and other objects, which will become apparent during the followingdetailed description, have been achieved by the inventors' discovery ofa method which uses a partially hydrolyzed wheat protein. The inventionhas been accomplished based on the finding.

Thus, the present invention provides:

(1) A processed fiber obtained by the steps of attaching a partiallyhydrolyzed wheat protein to a surface of a fiber and treating the fiberwith a transglutaminase.

(2) A processed fiber according to (1), wherein the partially hydrolyzedwheat protein is prepared by treating a wheat protein with an enzyme, anacid, or an alkali.

(3) A processed fiber according to (1) or (2), wherein the partiallyhydrolyzed wheat protein has a number average molecular weight of 700 to50,000.

(4) A method for producing a processed fiber, characterized bycomprising the steps of attaching a partially hydrolyzed wheat proteinto a surface of a fiber and treating the fiber with a transglutaminase.

(5) A method according to (4), wherein the partially hydrolyzed wheatprotein is prepared by treating a wheat protein with an enzyme, an acid,or an alkali.

(6) A method according to (4) or (5), wherein the partially hydrolyzedwheat protein has a number average molecular weight of 700 to 50,000.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the present invention, the partially hydrolyzed wheat protein means aproduct obtained by partially hydrolyzing a wheat gluten proteinmoderately with an enzyme, an acid, an alkali, etc., and does notinclude non-hydrolyzed wheat proteins and protein hydrolysates obtainedby excessively hydrolyzing a protein into amino acids. A commerciallyavailable partially enzyme-hydrolyzed wheat gluten protein (such asWGE80GPU available from DMV) may be used as it is. Also it can beprepared by hydrolyzing wheat gluten with an appropriateprotein-hydrolyzing enzyme. Alternatively, the partially hydrolyzedwheat protein may be a partially acid- or alkali-hydrolyzed wheat glutenprotein. The number average molecular weight of the partially hydrolyzedwheat protein is preferably 700 to 50,000 Da, more preferably 3,000 to40,000 Da, and particularly preferably 5,000 to 30,000 Da.

There are no particular limitations on the method for attaching thepartially hydrolyzed wheat protein to the fiber surface. For example,the partially hydrolyzed wheat protein may be attached to the fiber byimmersing the fiber in a solution prepared by dissolving or dispersingthe partially hydrolyzed wheat protein in a solvent such as water, or bycoating or spraying the partially hydrolyzed wheat protein onto thefiber. The partially hydrolyzed wheat protein may be present in at leasta gap or surface of a monofilament or staple in a thread of the fiber,and may adhere to or cover the monofilament or staple.

The concentration of the partially hydrolyzed wheat protein solution,used for immersing the fiber in the solution prepared by dissolving ordispersing the partially hydrolyzed wheat protein in the solvent such aswater or for coating or spraying the partially hydrolyzed wheat proteinonto the fiber, is preferably 1 to 30 g/L. The concentration is morepreferably 3 to 10 g/L from the viewpoints of cost and workability.

The amount of the partially hydrolyzed wheat protein attached to thefiber surface is preferably 0.1 to 3 g per 1 g of the fiber. The amountis more preferably 0.3 to 1 g from the viewpoints of cost andworkability.

The transglutaminase (which may be hereinafter referred to as TG) usedin the invention is an acyltransferase of EC 2.3.2.13, and has anactivity for catalyzing an acyl transfer reaction between a glutamineresidue donor and a lysine residue acceptor in the protein or peptide.Known transglutaminases are derived from various sources such asmammals, fishes, and microorganisms. The transglutaminase used in thepresent invention may be any enzyme as long as it has the aboveactivity, may be derived from any source, and may be a recombinantenzyme. Examples of the transglutaminases include those derived frommicroorganisms such as actinomycetes (see, Japanese Patent No. 2572716)and bacillus subtilis (see, Japanese Patent No. 3873408). The examplesfurther include those derived from guinea pig livers (see, JapanesePatent No. 1689614), those derived from microorganisms (see, WO96/06931), those derived from animals such as bovine blood and pigbloods those derived from fishes such as salmons and red sea breams(see, Seki, et al., Nippon Suisan Gakkaishi, 1990, 56, 125-132), andthose derived from oysters (see, U.S. Pat. No. 5,736,356). In addition,the examples further include those produced by genetic recombination(see, for example, Japanese Patent No. 3010589, JP-A-11-75876, WO01/23591, WO 02/081694, and WO 2004/078973), and disulfidebond-introduced transglutaminases with improved heat resistance (see, WO2008/099898).

A commercially available transglutaminase derived from a microorganismunder the product name of “ACTIVA” TG from Ajinomoto Co., Inc. is anexample which may be used in the invention.

Examples of methods to allow TG to act include a method of immersing thefiber in a solution containing the partially hydrolyzed wheat proteinand the TG, and a method of immersing the fiber in the partiallyhydrolyzed wheat protein solution followed by immersing it in a TGsolution. The pH of the solution containing the partially hydrolyzedwheat protein and the TG or the TG solution is preferably 4 to 12, morepreferably 5 to 8, from the viewpoints of the enzymatic reactivity andstability of the TG.

The enzymatic reaction time is not particularly limited as long as theenzyme can sufficiently act upon the substrate in the time. Though thefiber may be treated with the enzyme for a remarkably short time or along time, the reaction time is preferably 5 minutes to 24 hourspractically. Also the reaction temperature is not particularly limitedas long as the enzyme can maintain the activity. The reactiontemperature is preferably 0° C. to 80° C. practically.

The optimum addition amount of the TG, as the TG concentration of thesolution containing the partially hydrolyzed wheat protein and the TG orthe TG solution, is 10 to 3,000 U/L, preferably 100 to 3,000 U/L, morepreferably 1,000 to 3,000 U/L. The TG concentration may be appropriatelycontrolled depending on the type of the fiber, the TG reaction time, theTG reaction temperature, etc. When the TG concentration is more than3,000 U/L, the effect of the TG can be achieved but is inadequate tocompensate for the cost.

The addition amount of the TG is preferably 1 to 300 U per 1 g of thefiber, and is preferably 1 to 300 U per 1 g of the partially hydrolyzedwheat protein. The TG amount may be appropriately controlled dependingon the type of the fiber, the TG reaction temperature, etc.

The enzymatic activity is calculated as follows. The enzyme is used in areaction between substrates of benzyloxycarbonyl-L-glutaminylglycine andhydroxylamine, the thus generated hydroxamic acid is converted to aniron complex in the presence of trichloroacetic acid, the absorbance ofthe resultant complex is measured at 525 nm, and the amount of thehydroxamic acid is determined using a calibration curve to calculate theactivity. 1 U is defined as the amount of enzyme that generates 1 μmolof the hydroxamic acid in 1 minute at 37° C. at a pH of 6.0.

The processed fiber of the invention is a substance produced from anatural fiber such as sheep wool, silk, or cotton; a synthetic fibersuch as nylon, polyester, or acrylic; or a blended, mix-twisted, orcombined fiber thereof. In the case of using a protein-based fiber (suchas sheep wool or silk) or a polyamide-based fiber (such as nylon), theadhesion between the fiber and the protein is further improved becausethe terminal amino group contributes to the crosslink bonds by thetransglutaminase reaction.

Other features of the invention will become apparent in the course ofthe following descriptions of exemplary embodiments which are given forillustration of the invention and are not intended to be limitingthereof.

EXAMPLES Example 1

The following proteins and enzyme were used in the Examples.

Protein

Glutamine peptide A: a partially hydrolyzed wheat gluten proteinWGE80GPU available from DMV (number average molecular weight 9,650 D)Glutamine peptide B: a partially hydrolyzed wheat gluten protein B:WGE80GPA available from DMV (number average molecular weight 660 D)Gelatin A: a bovine-derived alkali-treated gelatin available fromKishida Chemical Co., Ltd.

Enzyme Transglutaminase (EC 2.3.2.13)

Enzyme source: derived from an actinomycete Streptomyces mobaraensisEnzymatic activity: 1,000 U/g

Approximately 1 g of a silk fabric (Standard adjacent fabric No. 2-1 ofa plain habutae silk according to JIS L 0803) was subjected to anexhaustion treatment at 40° C. for 1 hour in 100 ml of an aqueoussolution containing the glutamine peptide (A or B; 2 types) or thegelatin A in the same amount (1 g). After the exhaustion treatment usingthe glutamine peptide or gelatin, the silk fabric was dried, subjectedto an enzyme treatment at 40° C. for 1 hour in 100 ml of a Tris-HClbuffer solution (pH 7) containing 10 mg (100 U/L) of thetransglutaminase, and then dried. (Also a silk fabric, which was notsubjected to the protein exhaustion treatment, was treated with the TGas a control.)

The tear strength of the processed silk fabric was measured in Newton Nin the warp cutting direction by Pendulum method according to JIS L1096. Furthermore, the processed silk fabric was washed three times with1 L of distilled water at 40° C. for 10 minutes while stirring with astirrer, to evaluate the influence of the repeated water washing on thestrength of the fabric. Then, the fabric was dried, and the tearstrength was measured in the same manner as above.

As shown in Table 1, all the processed silk fabrics, exhaustion-treatedwith the glutamine peptide A or B or the gelatin A, exhibited increasedsilk fiber strengths. Particularly the glutamine peptide A-treatedfabric maintained the strength even after the washing, and exhibited thelargest strength increase. It is clear from the results that theglutamine peptide A was firmly attached to the silk fabric surface bythe transglutaminase reaction. In contrast, the gelatin-treated fabricdid not have a sufficient tear strength. Thus, the method of theinvention using the partially hydrolyzed wheat protein had moresignificant advantageous effects as compared with the method disclosedin JP-A-9-3773.

TABLE 1 Strength of silk fiber treated with various proteins. ProteinGlutamine Glutamine peptide A peptide B Gelatin A None None TG treatmentTreated Treated Treated Treated Not treated Tear After 7.3 5.1 4.9 4.53.8 strength treat- (N) ment After 7.4 5.2 5.0 4.4 Not washing deter-mined

Example 2

The following proteins, different from the proteins used in Example 1,were used in the experiment to evaluate the influence of the type andmolecular weight of protein.

Protein

Glutamine peptide C: a partially hydrolyzed wheat gluten protein SWP500available from Amylum (number average molecular weight 5,000 to 30,000D, estimated from SDS-PAGE)Glutamine peptide D: a self-prepared partially hydrolyzed wheat glutenprotein (number average molecular weight 3,000 D)Glutamine peptide E: a partially hydrolyzed wheat gluten protein GLUPAL30 available from Katayama Chemical, Inc. (hydrolyzed by acid andalkali, number average molecular weight 40,000 to 50,000 D)

The glutamine peptide D was prepared by partially hydrolyzing a wheatgluten with a protease (a Bacillus amyloliquefaciens MRP protein) to anumber average molecular weight of 3,000 D. After the hydrolysis,insoluble components were removed, and the resultant peptide wasspray-dried into the powder form.

Approximately 1 g of a silk fabric (Standard adjacent fabric No. 2-1 ofa plain habutae silk according to JIS L 0803) was subjected to anexhaustion treatment at 40° C. for 1 hour in 100 ml of an aqueoussolution containing one of the three glutamine peptides in the sameamount (1 g). After the glutamine peptide exhaustion treatment, the silkfabric was dried, subjected to an enzyme treatment at 40° C. for 1 hourin 400 ml of a Tris-HCl buffer solution (pH 7) containing 40 mg (100U/L) of the transglutaminase, and then dried. The tear strength of theprocessed silk fabric was measured in Newton N in the warp cuttingdirection by Pendulum method according to JIS L 1096.

The results are shown in Table 2 together with the results of Example 1.The tear strength of the glutamine peptide-treated fabric was improvedwith the increase of the average molecular weight. Particularly theglutamine peptide C-treated fabric had a smooth texture. Also theglutamine peptide E-treated fabric exhibited an increased tear strengtheven though hydrolyzed with acid and alkali.

TABLE 2 Influence of protein molecular weight on silk fiber strength.Protein Glu- Glu- Glu- Glu- tamine tamine tamine tamine peptide peptidepeptide peptide Glutamine Not B D A C peptide E treated Number 660 3,00010,000 5,000 to 40,000 to — average 30,000 50,000 molecular weight (D)Tear 5.1 6.9 7.3 11.2 8.7 3.8 strength (N)

Example 3

The glutamine peptide C described in Example 2 was used in the followingexperiment to evaluate the influence of the concentrations of theprotein and transglutaminase.

Approximately 1 g of a silk fabric (Standard adjacent fabric No. 2-1 ofa plain habutae silk according to JIS L 0803) was subjected to anexhaustion treatment at 40° C. for 1 hour in 100 ml of an aqueoussolution containing the glutamine peptide C. After the glutamine peptideC exhaustion treatment, the silk fabric was dried, subjected to anenzyme treatment at 40° C. for 1 hour in 100 ml of a Tris-HCl buffersolution (pH 7) containing the transglutaminase, and then dried. Theconcentrations of the protein and transglutaminase used in thetreatments are shown in Table 3. The tear strength of the processed silkfabric was measured in Newton N in the warp cutting direction byPendulum method according to JIS L 1096.

The results are shown in Table 3. A significant effect was achieved at aprotein concentration of 1 g/L or more, and the tear strength of theprocessed fabric was greatly improved with the increase of theconcentration. The tear strength was greatly improved under all theexamined transglutaminase concentrations.

TABLE 3 Influence of protein concentration and transglutaminaseconcentration on silk fiber strength. Protein concentration (g/L) 0.10.3 1 3 10 30 Enzymatic activity (U/L) 1,000 1,000 1,000 1,000 1,0001,000 Tear strength (N) 4.67 4.55 6.08 8.88 11.46 12.91 Proteinconcentration (g/L) 10 10 10 10 0 0 Enzymatic activity (U/L) 10 30 1003,000 3,000 0 Tear strength (N) 12.39 10.56 11.39 11.90 4.33 4.10

Example 4

1 g of a polyester fabric (Standard adjacent fabric of a polyesteraccording to JIS L 0803) was subjected to an exhaustion treatment at 40°C. for 1 hour in 100 ml of an aqueous solution containing the glutaminepeptide A or the gelatin A in the same amount (1 g). After theexhaustion treatment using the glutamine peptide A or gelatin A, thepolyester fabric was dried, subjected to a TG treatment at 40° C. for 1hour in 100 ml of a Tris-HCl buffer solution (pH 7) containing 10 mg(100 U/L) of the transglutaminase, and then dried. In addition, apolyester fabric, which was not subjected to the protein exhaustiontreatment, was treated with the enzyme as a control.

The tear strength of the processed polyester fabric was measured inNewton N in the warp cutting direction by Pendulum method according toJIS L 1096. The processed polyester fabric was subjected to a waterabsorbency test using a dropping method according to JIS L 1907 toevaluate the change of the surface hydrophilicity of the fabric. In thisdropping method, the water droplet infiltration area was measured in cm²1 minute after dropping water. Furthermore, the processed polyesterfabric was subjected to a repeated washing test under conditions of A-2method according to JIS L 0844 (40° C., 5-g/L detergent, stirred at 42rpm, 30 minutes) to evaluate the influence of the repeated washing onthe surface hydrophilicity of the fabric. The detergent was used in thefirst washing and not used in the second washing. The washed fabric wasdried, and then the surface hydrophilicity was measured in the abovemanner.

As shown in Table 4, the processed polyester fabric, exhaustion-treatedwith the glutamine peptide A, exhibited an increased tear strength. Theprocessed polyester fabrics, exhaustion-treated with the glutaminepeptide A or the gelatin A, had greatly increased surfacehydrophilicities. However, only the glutamine peptide-treated fabricmaintained the surface hydrophilicity even after the washing test. Itwas confirmed that when the glutamine peptide A was attached to thepolyester surface and the polyester fabric was treated with the TG, theresultant processed polyester fabric had the increased surfacehydrophilicity even after the washing. The polyester is disadvantageousonly in that it cannot absorb water (perspiration), and therefore isoften blended with a cotton to diminish the disadvantage. It issuggested that the surface water infiltration of the polyester can beimproved by the method of the invention to improve the disadvantage.

In contrast, the gelatin-treated polyester fabric did not havesufficient tear strength and water droplet infiltration area. Thus, themethod of the invention using the partially hydrolyzed wheat protein hadmore significant advantageous effects as compared with the methoddisclosed in JP-A-9-3773.

TABLE 4 Strength and water droplet infiltration area of polyestertreated with various proteins. Protein Glutamine peptide A Gelatin ANone None TG treatment Treated Treated Treated Not treated Tear strength(N) After 10.6 8.7 9.0 8.5 treatment Water droplet After 3.02 1.82 1.350.19 infiltration area treatment (cm²) After 2.89 0.34 0.48 0.37 washing

Example 5

1 g of a nylon fabric (Standard adjacent fabric of a nylon according toJIS L 0803) was subjected to an exhaustion treatment at 40° C. for 1hour in 100 ml of an aqueous solution containing the glutamine peptide Aor the gelatin A in the same amount (1 g). After the exhaustiontreatment using the glutamine peptide A or gelatin A, the nylon fabricwas dried, subjected to a TG treatment at 40° C. for 1 hour in 100 ml ofa Tris-HCl buffer solution (pH 7) containing 10 mg (100 U/L) of thetransglutaminase, and then dried. Also a nylon fabric, which was notsubjected to the protein exhaustion treatment, was treated with theenzyme as a control.

The tear strength of the processed nylon fabric was measured in Newton Nin the warp cutting direction by Pendulum method according to JIS L1096. The processed nylon fabric was subjected to a water absorbencytest using a dropping method according to JIS L 1907 to evaluate thechange of the surface hydrophilicity of the fabric. In this droppingmethod, the water droplet infiltration area was measured in cm² 1 minuteafter dropping water. Furthermore, the processed nylon fabric wassubjected to a repeated washing test under conditions of A-2 methodaccording to JIS L 0844 (40° C., 5-g/L detergent, stirred at 42 rpm, 30minutes) to evaluate the influence of the repeated washing on thesurface hydrophilicity of the fabric. The detergent was used in thefirst washing and not used in the second washing. The washed fabric wasdried, and then the surface hydrophilicity was measured in the abovemanner.

As shown in Table 5, the processed nylon fabrics, exhaustion-treatedwith the glutamine peptide A or the gelatin A, exhibited increased tearstrengths. The processed nylon fabrics, exhaustion-treated with theglutamine peptide A or the gelatin A, had increased surfacehydrophilicities. The water droplet infiltration area of the glutaminepeptide A-treated fabric was four or more times as large as that of thegelatin A-treated fabric. Furthermore, only the glutaminepeptide-treated fabric maintained the surface hydrophilicity even afterthe washing test. It was confirmed that when the glutamine peptide A wasattached to the nylon surface and the nylon fabric was treated with theTG, the resultant processed nylon fabric had the increased surfacehydrophilicity even after the washing. In contrast, the gelatin-treatednylon fabric did not have a sufficient water droplet infiltration area.Thus, the method of the invention using the partially hydrolyzed wheatprotein had more significant advantageous effects as compared with themethod disclosed in JP-A-9-3773.

TABLE 5 Strength and water droplet infiltration area of nylon treatedwith various proteins. Protein Glutamine peptide A Gelatin A None NoneTG treatment Treated Treated Treated Not treated Tear strength (N) After28.1 27.2 24.6 22.7 treatment Water droplet After 4.58 1.00 0.18 0.37infiltration area treatment (cm²) After 1.77 0.31 0.27 0.16 washing

Example 6

1.25 g of a polyester fabric (Standard adjacent fabric of a polyesteraccording to JIS L 0803) was subjected to an exhaustion treatment at 40°C. for 1 hour in 200 ml of an aqueous solution containing the glutaminepeptide A in the same amount (1.25 g). After the peptide exhaustiontreatment, the polyester fabric was dried, subjected to a TG treatmentat 40° C. for 1 hour in 200 ml of a Tris-HCl buffer solution (pH 7)containing 200 mg (1,000 U/L) of the transglutaminase, and then dried.In addition, a polyester fabric, which was not subjected to the proteinexhaustion treatment and the enzyme treatment, and a polyester fabric,which was subjected only to the protein exhaustion treatment, wereprepared as controls.

The processed polyester fabric was subjected to a repeated washing testunder conditions of A-2 method according to JIS L 0844 (40° C., 5-g/Ldetergent, stirred at 42 rpm, 30 minutes). In each washing, the fabricwas washed using the detergent, washed without the detergent, and thennaturally dried. A water absorbency test using a dropping methodaccording to JIS L 1907 was carried out before the repeated washing,after the first washing, after the fifth washing, and after the tenthwashing. In this dropping method, the water droplet infiltration areawas measured in cm² 1 minute after dropping water.

The results are shown in Table 6. The processed polyester fabric,treated only with the glutamine peptide A and not treated with thetransglutaminase, exhibited no effects after the fifth washing. Incontrast, the processed polyester fabric, treated with both theglutamine peptide A and the transglutaminase, maintained theadvantageous effects even after the tenth washing.

TABLE 6 Influence of washing number on water droplet surface area ofTG-treated polyester. Water droplet infiltration area (cm²) Before Afterfirst After fifth After tenth washing washing washing washing — 0.940.94 0.94 0.94 Glutamine peptide A 8.75 2.81 0.94 0.94 Glutamine peptideA + TG 9.06 5.31 4.69 3.75

Example 7

The glutamine peptide A was used in the following experiment to evaluatethe influence of the concentrations of the protein and transglutaminase.

1.25 g of a polyester fabric (Standard adjacent fabric of a polyesteraccording to JIS L 0803) was subjected to an exhaustion treatment at 40°C. for 1 hour in 200 ml of an aqueous solution containing the glutaminepeptide A in the same amount (1.25 g) or one-tenth thereof (0.125 g).After the peptide exhaustion treatment, the polyester fabric was dried,subjected to a TG treatment at 40° C. for 1 hour in 200 ml of a Tris-HClbuffer solution (pH 7) containing 2,000 or 200 mg (10,000 or 1,000 U/L)of the transglutaminase, and then dried. In addition, a polyesterfabric, which was subjected only to the protein exhaustion treatmentwithout the enzyme treatment, was prepared as a control.

The processed polyester fabric was subjected to a repeated washing testunder conditions of A-2 method according to JIS L 0844 (40° C., 5-g/Ldetergent, stirred at 42 rpm, 30 minutes). In each washing, the fabricwas washed using the detergent, washed without the detergent, and thennaturally dried. A water absorbency test using a dropping methodaccording to JIS L 1907 was carried out before the repeated washing,after the first washing, after the fifth washing, and after the tenthwashing. In this dropping method, the water droplet infiltration areawas measured in cm² 1 minute after dropping water.

The results are shown in Table 7. The processed polyester fabricsproduced using the ten-fold enzyme concentration or the one-tenthpeptide concentration maintained the advantageous effects even after thetenth washing.

TABLE 7 Influence of washing number on water droplet surface area ofTG-treated polyester Water droplet infiltration area (cm²) After AfterAfter Before first fifth tenth washing washing washing washing Glutaminepeptide A (6.25 g/L) 6.90 0.90 0.90 0.90 Glutamine peptide A (6.25g/L) + 6.90 6.90 4.70 4.70 TG (10,000 U/L) Glutamine peptide A (0.625g/L) 9.10 0.90 0.90 0.90 Glutamine peptide A (0.625 g/L) + 9.10 4.704.70 2.10 TG (10,000 U/L)

Example 8

1.25 g of a polyester fabric (Standard adjacent fabric of a polyesteraccording to JIS L 0803) was subjected to a glutamine peptide exhaustiontreatment and a transglutaminase treatment simultaneously at 40° C. for1 hour in 100 ml of a Tris-HCl buffer solution (pH 7) containing thesame amount (1.25 g) of the glutamine peptide A and 1,000 mg (10,000U/L) of the transglutaminase.

The processed polyester fabric was subjected to a repeated washing testunder conditions of A-2 method according to JIS L 0844 (40° C., 5-g/Ldetergent, stirred at 42 rpm, 30 minutes). In each washing, the fabricwas washed using the detergent, washed without the detergent, and thennaturally dried. A water absorbency test using a dropping methodaccording to JIS L 1907 was carried out before the repeated washing,after the first washing, after the fifth washing, and after the tenthwashing. In this dropping method, the water droplet infiltration areawas measured in cm² 1 minute after dropping water.

The results are shown in Table 8. Even when the glutamine peptide Aexhaustion treatment and the transglutaminase treatment were carried outat the same time, the resultant processed polyester fabric maintainedthe advantageous effects even after the tenth washing.

TABLE 8 Water droplet infiltration area (cm²) Before After first Afterfifth After tenth washing washing washing washing Glutamine peptide A +TG 12.50 6.25 4.40 2.10

INDUSTRIAL APPLICABILITY

In the present invention, the processed fiber having increased strengthand excellent water absorbency can be easily produced with low cost.Thus, the invention is extremely useful in the textile industrial field.

Where a numerical limit or range is stated herein, the endpoints areincluded. Also, all values and subranges within a numerical limit orrange are specifically included as if explicitly written out.

Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that, within the scope of the appended claims, theinvention may be practiced otherwise than as specifically describedherein.

All patents and other references mentioned above are incorporated infull herein by this reference, the same as if set forth at length.

1. A processed fiber, which is prepared by attaching a partiallyhydrolyzed wheat protein to a surface of a fiber and treating the fiberwith a transglutaminase.
 2. A processed fiber according to claim 1,wherein said partially hydrolyzed wheat protein is prepared by treatinga wheat protein with an enzyme, an acid, or an alkali.
 3. A processedfiber according to claim 1, wherein said partially hydrolyzed wheatprotein has a number average molecular weight of 700 to 50,000.
 4. Aprocessed fiber according to claim 2, wherein said partially hydrolyzedwheat protein has a number average molecular weight of 700 to 50,000. 5.A fabric, which comprises at least one fiber according to claim
 1. 6. Afabric, which comprises at least one fiber according to claim
 2. 7. Afabric, which comprises at least one fiber according to claim
 3. 8. Afabric, which comprises at least one fiber according to claim
 4. 9. Amethod for producing a processed fiber, comprising: attaching apartially hydrolyzed wheat protein to a surface of a fiber and treatingsaid fiber with a transglutaminase.
 10. A method according to claim 9,wherein said partially hydrolyzed wheat protein is prepared by treatinga wheat protein with an enzyme, an acid, or an alkali.
 11. A methodaccording to claim 9, wherein said partially hydrolyzed wheat proteinhas a number average molecular weight of 700 to 50,000.
 12. A methodaccording to claim 10 wherein said partially hydrolyzed wheat proteinhas a number average molecular weight of 700 to 50,000.
 13. A methodaccording to claim 9, wherein said fiber is contained in a fabric.
 14. Amethod according to claim 10, wherein said fiber is contained in afabric.
 15. A method for producing a processed fiber, comprisingcontacting a fiber with a partially hydrolyzed wheat protein and atransglutaminase, to obtain a fiber which in which said partiallyhydrolyzed wheat protein is attached to said fiber.
 16. A methodaccording to claim 15, wherein said fiber is contacted with saidpartially hydrolyzed wheat protein prior to being contacted with saidtransglutaminase.
 17. A method according to claim 15, wherein said fiberis contacted with said partially hydrolyzed wheat protein and saidtransglutaminase simultaneously.
 18. A method according to claim 15,wherein said partially hydrolyzed wheat protein is prepared by treatinga wheat protein with an enzyme, an acid, or an alkali.
 19. A methodaccording to claim 15, wherein said partially hydrolyzed wheat proteinhas a number average molecular weight of 700 to 50,000.
 20. A methodaccording to claim 15, wherein said fiber is contained in a fabric.